perf: add benchmark for title api encode/decode

sdgb-api/benches/enc_dec.rs

@@ -0,0 +1,22 @@
+#![feature(test)]
+extern crate test;
+
+use sdgb_api::title::{MaiVersionExt, Sdgb1_50};
+
+#[bench]
+pub fn sdgb_150_enc_short(b: &mut test::Bencher) {
+    b.iter(|| _ = Sdgb1_50::encode(b"Hello world"));
+}
+
+#[bench]
+pub fn sdgb_150_enc_4k(b: &mut test::Bencher) {
+    let data = [1u8; 4096];
+    b.iter(|| _ = Sdgb1_50::encode(data));
+}
+
+#[bench]
+pub fn sdgb_150_dec_4k(b: &mut test::Bencher) {
+    let data = [1u8; 4096];
+    let enc_data = Sdgb1_50::encode(data).unwrap();
+    b.iter(|| _ = Sdgb1_50::decode(enc_data.clone()));
+}